How-To: Ball-In-Cage Switch

Sean Ragan just put up a tutorial for this simple analog tamper-detecting switch for guarding his garden over on Make: Projects:

This clever mechanical switch remains open so long as it is balanced in an upright position. But disturb it in any way, and the ball falls against the bars of the cage and closes the circuit. Use it to control an alarm to protect your valuables, or to trigger a camera to photograph wildlife.